For the Birds Radio Program: Black-throated Green Warbler
Black-throated Green Warbler One of the signs that spring is definitely here to stay is the arrival of the Black-throated Green Warbler. This bird’s long name belies its tiny size, and it also belies its overall color. We do certainly notice the black throat, at least on adult males, but reports of the birds being green seem vastly exaggerated. Much more conspicuous is the bright yellow face, not as clean and brilliant as the closely-related and endangered Golden-cheeked Warbler, which breeds in Texas, or the Pacific slope’s Hermit Warbler, but our eastern species is beautiful nonetheless. If Black-throated Green Warblers are pretty to look at, they’re even prettier to listen to. I learned their song as zee-zee-zoo-zoo-zee or zee-zee-zee-zoo-zee, but others have learned it as trees, trees, whispering trees. Because of the pattern, this is one of the easiest warbler songs to learn, and it’s also one of the easiest to hear, since Black-throated Green Warblers sing during migration as well as once they reach their territories, and they’re very persistent singers. One ornithologist counted songs of a Black-throated Green Warbler on his study area—this was just an everyday Black-throated Green Warbler, not a champion singer or anything—and counted 466 songs in one hour. That’s over 7 songs per minute, so he was singing more than once every 8 seconds. The two songs male Black-throated Green Warblers sing apparently have two different meanings. The “zee-zee-zee-zoo-zee” song is given near the middle of his territory, largely in the beginning of the breeding season, and apparently is intended for attracting females. The zee-zee-zoo-zoo-zee song is mostly sung around the territory’s margins, and apparently is used to keep other males out of the territory. Black-throated Green Warblers are Neotropical migrants. A handful do winter in southernmost Texas and a stretch of Mexico, but the bulk of them get farther south, all the way to northern South America. I’ve seen them in mid-winter in Guatemala, where they were flocking with all three of their close relatives—Hermit, Golden-cheeked, and Townsend’s warblers. It was thrilling to see them, but I must say that at the time I was more excited about the Golden-cheeked, which was a lifer, maybe because I was just seeing and not hearing any of them, at least not giving their songs. Black-throated Green Warblers often nest at or below eye level in our northern coniferous forests, but are so secretive around the nests that they’re hard to find. Like many small birds, they use a lot of spider silk in construction—they also use twigs, grass, and bark, and line the nest with moss, hair, and feathers. I presume they get the hair the way I watched a Tufted Titmouse last spring getting long hairs for its nest—by plucking them from the tail of a sleeping raccoon. Black-throated Green Warblers are one of the first warblers to arrive on their territories in May, and they persist in singing well into July. I’ve managed to call them in for close looks by making a poor imitation of their song with my voice—apparently the rhythm is more important than the tonal quality. So practice up and with luck you should get some splendid looks at this lovely little bird.